Means for controlling the connection between underground high voltage conductors



Feb. 25, 1964 H. J. BARTA 3,122,658

MEANS FOR CONTROLLING THE CONNECTION BETWEEN UNDERGROUND HIGH VOLTAGECONDUCTORS Filed June 22, 1961 3 Sheets-Sheet 1 Emu/2d Lead INVENTOR.flrzcy Jfiarza, BY

H. J. BARTA Feb. 25, 1964 3,122,658 MEANS FOR CONTROLLING THE CONNECTIONBETWEEN UNDERGROUND HIGH VOLTAGE CONDUCTORS 3 Sheets-Sheet 2 Filed June22, 1961 d m m WW w Y M W m N m H Y N B W m a a ,E 7 ww 1 I w 6 7wwwmwmwww m my 3 wk 6 1 w? I 3,122,658 MEANS FOR CONTROLLING THEcoNNEcTI0N BETWEEN UNDERGROUND HIGH VOLTAGE CONDUCTORS Filed June 22,1961 H. J. BARTA Feb. 25, 1964 5 Sheets-Sheet 3 I!!! alf rlflffllllIlll'llllilllll'll r INVENTOR. Hazy 1.73am W W E T a w m a w w m wmw/r. m E EH United States Patent 3,122,653 MEANS FOR CQNTRGLLING THECGNNECTHON BETWEEN UNDERGRGUND HEGH VOLTAGE C(DNDUCTORS Henry .1.Barter, Broolriield, 113., assignor to S & C Electric Company, Chicago,111., a corporation of Delaware Fiietl June 22, 1961, Ser. No. 118,96717 Claims. (Cl. sin-94) This invention relates, generally, to circuitconnecting means and it has particular relation to disconnecting fusesand disconnecting switches for interconnecting underground insulatedconductors.

Among the objects of this invention are: To provide new and improvedmeans for interconnecting sections of buried insulated conductorsemployed for the distribution of relatively high voltage alternatingcurrent; to provide for the direct burial of disconnecting fuses andswitches for use in protecting and sectionalizing underground electricpower distribution circuits; to interconnect adjacent ends of a pair ofburied insulated conductors with vertically spaced terminals in a buriedinsulating housing and to detachably interconnect these terminals withremovable connecting conductor means; to employ for the connectingconductor means either a fuse of the expulsion or current limiting typeor a disconnecting blade, these devices being interchangeable andcapable of application to and removal from the spaced terminals; toprovide at the lower end of the insulating housing a metallic exhaustchamber for receiving the are products incident to blowing of the fuse;to prevent the return of the arc products to the use once they have beendischarged into the exhaust chamber; to seal the exhaust chamber to theinsulating housing and prevent the entrance of ground moisture; tolocate the insulating housing at the lower end of an access tube thatextends to the ground surface and through which an operator, such as alive line stick, can be inserted to apply or remove the connectingconductor means; to seal the insulating housing to the access tube andprevent the entrance of ground water; to provide a ground rod extendingthrough the access tube and along the insulating housing and metallicexhaust chamber and embedded in the adjacent ground; and to interconnectthe ground rod with metallic shields surrounding the spliced connectionsbetween the insulated conductors and terminal members extending from theterminals in the insulating housing or metallic shields forming part ofthe cable.

Other objects of this invention will, in part, be obvious and in partappear hereinafter.

in the drawings:

FIG. 1 is a view, somewhat schematic in character and partially invertical section, showing a typical application of the presentinvention.

FIGS. 2A-2B taken together with the former positioned above the lattershow a longitudinal vertical sectional view of one embodiment of theconnecting means constructed in accordance with this invention.

FIG. 3 is a horizontal sectional view taken generally along the line 3-3of FIG. 2B.

FIGS. 4A-4B taken together with the former positioned above the lattershow a vertical sectional view of another embodiment of the connectingmeans constructed in accordance with this invention.

FIG. 5 is a horizontal sectional view taken generally along the line 5-5of FIG. 48.

Referring now particularly to FIG. 1 it will be observed that thereference characters and 11 designate, generally, insulated high voltageconductors comprising, respectively, conductors 12 and 13, either solidor stranded, and overlying insulation sheaths 14 and 15.

ice

The insulated high voltage conductors 10 and 11 are of conventionalconstruction and are employed for the distribution of high voltagealternating current, principally for use in residential areas toenergize distribution transformers that reduce the high voltage to lowervoltage suitable for residential use. They may operate at voltages ofthe order of 2300 volts andhigher and may form a part of a distributioncircuit of the ring type. Usually the insulated high voltage conductors10 and 11 constitute one phase of a polyphase distribution system havinga grounded neutral. In accordance with present conventional practice theinsulated high voltage conductors 10 and 11 are located well beneath thesurface of the ground which is indicated at 16. Ordinarily, a trench isexcavated for receipt of the insulated high voltage conductors 10 and 11and the equipment associated therewith to be described presently.

It is desirable to provide connecting means, shown generally at 17, forinterconnecting the insulated high voltage conductors 10 and 11 in orderto sectionalize them and to provide for protection against theoccurrence of a fault. The connecting means 17 includes an insulatinghousing 18 that may be :formed of molded plastic material such as aphenolic condensation product. Also, the insulating housing 18 can beformed of fiber glass or various combinations of it with other plasticinsulating materials as may be desired. Extending laterally from theinsulating housing 18 and formed integrally therewith are a lowerinsulating arm 20 and an upper insulating arm 21. It will be observedthat the lower and upper insulating arms 20 and 21 extend toward theinsulated high voltage conductors 10 and 11, respectively, and that eachof them includes a conductor in the form of a lower terminal member 22and an upper terminal member 23. As shown more clearly in FIGS. 2A2B andFIG. 3 of the drawings the terminal members 22 and 23 are rod shaped. Asindicated in FIG. 3 a metallic connecter 24 is provided on the outer endof each of the terminal members 22 and 23 for receiving thecorresponding end of the conductor 12 or 13 in order to provide acircuit connection thereto. It will be understood that the ends of theconductors 12 and 13 are spliced to the respective terminal members 22and 23 by the metallic connecters 24 in conventional manner and that theresulting splices are surrounded by insulation 2525 that, in turn, aresurrounded by metallic shields 26-46. The splices thus provided arecon-ventional cable splices and the insulating arms 20 and 21 areprovided to facilitate such splices.

The metallic shields 262 6 are connected by ground conductors '27-27 toa metallic ground rod 218 which is embedded in the ground in thevicinity of the connecting means 17 and which extends along theinsulating housing 18 and upwardly to ground level 16 as indicated inFIG. 1.

Since the connecting means 17 together with the insulated high voltageconductors 10 and 11 is permanently buried beneath ground level 16, itis desirable that provision be made for entrance to the connecting means17. Accordingly, an access tube 31 is provided which may be either ofmetallic construction or of insulating material. Its lower endtelescopes over the upper end of the insulating housing 18 and a sealinggasket 32 is provided therebetween to exclude ground Water. It will beobserved that the ground rod 28 extends through the sealing gasket 32and upwardly inside the access tube 31. If the latter is formed ofmetal, it is connected at 33 to the ground rod 28. At its upper end theaccess tube 31 is provided with a suitable closure 34 that can bearranged so that a lock 35 must be removed by authorized personnelbefore the access tube 31 can be opened.

3 Referring now particularly to FIGS. 2A-2B of the drawings, it will beobserved that the lower and upper terminal members 22 and 23 areconnected interiorly of the insulating housing 18 to lower and upperterminals 36 and 37 respectively. These terminals are generallycylindrical in configuration and conform to the inner periphery of theinsulating housing 18, being held in place therein by the terminalmembers 22 and 23 which extend therethrough and are headed over on theinner sides thereof.

The lower terminal 36 is of special construction. It includes a lowerradially inwardly extending flange 38 and an upper radially inwardlyextending flange 39, the latter being provided with slots 48-48 as shownmore clearly in FIG. 3 of the drawings. The upper terminal 37 is similarto the lower terminal 36 except that it is only provided with an upperradially inwardly extending flange 41 that has slots 42-42 which arealigned with slots 48-40 in the flange 39 of the lower terminal 36.

The slots 40 48 in the flange 39 and the slots 42-42 in the flange 41are provided for receiving outstanding flanges 43-43 which arepositioned at the upper and lower ends of terminal assemblies 44-44which are mounted at the upper and lower ends of a tubular liner 45 of asuitable insulating material such as nylon or the like which gives offan arc extinguishing medium when it is subjected to the heat of an arc.Each of the terminal assemblies 44 includes a pair of L-shaped brackets46 46 the longer portions of which are secured by rivets 47-47 to theouter sides of the respective end of the liner 45. The short portions ofthe L-shaped brackets 46-46 are secured by rivets 48-48 to lateralflanges 49-49 of cylindrical contacts 58-50 which have contact fingers51-51 formed integrally therewith and extending upwardly and downwardlyas the case may be. Garter springs 52-52 serve to bias the contactlingers 51-51 inwardly.

The tubular liner 45 is inserted through the upper end of the insulatinghousing 18 in such position that the outstanding flanges 43-43 on thelower terminal assembly 44 are in alignment with the slots 42-42 in theflange 41 on the upper terminal 37. These slots also permit the passageof the outstanding flanges 43-43 of the upper terminal assembly 44 whenthe tubular liner 4-5 has been inserted to such an extent that theoutstanding flanges 43-43 on the lower terminal assembly 44 have passedthrough the slots 40-48 in the upper flange 39 on the lower terminal 36.Now the tubular liner 45 is turned through about 90 from the positionshown in FIG. 3 and the outer ends of the flanges 43-43 engage contactfingers 53-53 which are secured by rivets 54-54 to the inner side of therespective terminals 36 and 37. Because of the rotation of the tubularliner 45, the respective ends of the flanges 43-43 load the associatedcontact fingers 53-53, which are resilient in character, with the resultthat good contact engagement is provided therewith and the circuits arecompleted from the lower and upper terminal members 22 and 23 throughthe terminal assemblies 44-44 to the contact fingers 51-51 thereof. Inorder to hold the tubular liner 45 in the rotated position an annularfitting 55 is located within the lower terminal 36 and it is biasedupwardly by a coil compression spring 56 which reacts between the underside of it and the upper side of the lower flange 38 as will beunderstood more clearly from a consideration of FIG. 2B. The arrangementis such that, when the tubular liner 45 is rotated through the properextent, the spring 56 urges the flanges 53-53 into detents requiringthat an endwise downward force be applied to the tubular liner 45against the force exerted by the coil compression spring 56 to removethe flanges 43-43 on the lower terminal assembly 44 before it can berotated to the released position where the flanges 43-43 are inalignment with the slots 40-40 and the slots 42-4-2.

Provision is made in accordance with this invention for interconnectingthe upper and lower terminal assemblies 44-44 at the upper and lowerends of the tubular liner 45 for, in turn, interconnecting ordisconnecting the lower and upper terminal members 22 and 23. For thispurpose connecting conductor means, shown generally at 59, is provided.This means may be in the form of a disconnecting blade or rod, such asshown in U.S. Patent No. 2,316,470, issued April 13, 194-3, or it may bein the form of an expulsion fuse constructed generally as disclosed incopending application Serial No. 39,885, filed June 30, 1960, now Patent3,094,597. The present invention is disclosed as embodying for theconnecting conductor means 59 an expulsion fuse certain details of theconstruction of which will now be set forth.

Referring particularly to FIGS. ZA-ZB, it will be observed that theconnecting conductor means 59 in the form of an expulsion fuse includesa lower fuse terminal 68 which constitutes a discharge terminal and anupper fuse terminal 61, these terminals being located at the ends of afuse tube 62 of insulating material and being arranged to engage thecontact fingers 51-51 of the terminal assemblies 44-44 previouslydescribed. Within the fuse tube 62 is a liner 63 of boric acid cakes orsimilar material having a common bore 64 therethrough in which a movablerod-like terminal 65 extends. The lower end of the rod-like terminal isconnected by a fusible element 66 and a strain Wire 67 to a terminal 68that extends radially inwardly from the lower fuse terminal 60. At itsupper end, FIG. 2A, a coiled flexible cable 69 interconnects therod-like terminal 65 to the lower end of a metallic tube 70 whichextends upwardly through the fuse tube 62 and has a metallic bushing 71secured to its upper end that is threaded into the lower end of theupper fuse terminal 61. A coil tension spring 72 strained between theupper end of the metallic tube 70 and the upper end of the rod-liketerminal 65 serves to bias the latter upwardly for moving the rod-liketerminal 65 upwardly through the bore 64 when the fusible element 66 andstrain wire 67 blow upon the occurrence of predetermined overload. It isdesirable that provision be made for receiving the products of the aredischarged through the lower fuse terminal 60 on blowing of the fusibleelement 66 and strain wire 67. For this purpose a metallic exhaustchamber 75 is located at the lower end of the insulating housing 18 andhas a sealed connection therewith at 76. At its lower end the metallicexhaust chamber 75 has a closure 77 which is held in place and sealedagainst the entrance of ground water by the inturned lower end 78 of themetallic exhaust chamber 75. Any suitable cooling and condensing means,indicated generally at 79, can be provided within the metallic exhaustchamber 75. For example, the cooling and condensing means may bein theform of plates of metal or wire screen or combinations of these elementsor similar elements suitable for cooling and condensing the are productsquickly and limiting the pressure developed incident to blowing of thefusible element 66 and strain wire 67.

it is desirable to use the connecting conductor means 59 as adisconnecting switch in order to disconnect the insulated high voltageconductor 16 from the insulated high voltageconductor 11. In addition itis desirable that the are products be prevented from reentering the fusetube 62 once they have been discharged therefrom. Accordingly, a trailer82 of insulation is provided. The trailer 82 is formed of suitablematerial, such as methylmethacrylate resin or other insulating materialcapable of evolving an arc extinguishing medium when subjected to theheat of an arc. The trailer 82 is mounted at the lower end of the lowerfuse terminal 66 and is arranged to be moved upwardly along with thefuse tube 62 when the connecting conductor means 59 is withdrawn forcircuit isolating purposes. The are drawn between the lower end of thelower fuse terminal 6% and the contact fingers 51-51 of the lowerterminal assembly 44 is quickly extinguished since it is drawn over theouter surface of the trailer 82 and the inner surface of the tubularliner 45. The trailer 82 not only functions as an arc extinguishingdevice but also it functions as a check valve to prevent the reentry ofthe are products into the fuse tube 62 once they have been dischargedtherefrom. For this purpose a stem 83 is provided on which the trailer82 is slidably mounted. The upper end of the stem i5? is anchored to atransverse spider or bridge 84 within the lower fuse terminal 60. Itwill be understood that the s ider or bridge 84 is so constructed thatit presents a minimum of obstruction to the flow of the are productsdownwardly through the lower fuse terminal dd. At its lower end the stem83 has a head 85 and between it and the upper end of the trailer 82 acoil compression spring 86 is strained and it acts to bias the trailer82 upwardly. The upper end of the trailer 82 is protected from the areproducts by an overlying metallic washer 37 which is of suitable dishshape to overlie the conically shaped upper end of the trailer 82. Itwill be understood that the pressure incident to the blowing of thefusible element 66 and strain wire 67 is usually sufiicient to move thetrailer 82 downwardly against the biasing action of the coil compressionspring 86 a suiiicient distance to permit the discharge of the areproducts. However, when the pressure ceases, the spring 86 immediatelyreturns the trailer 32 to the closed position shown in FIG. 23 with theresult that the are products, and particularly the gas incident thereto,once discharged into the lower end of the insulating housing 18 and intothe metallic exhaust chamber '75 cannot return to the interior of thefuse tube 62.

Since the insulating housing 18 is permanently buried below the groundlevel 16 it is desirable to provide for the application and removal ofthe connecting conductor means 59 through the access tube 31 byinserting a suit able live line stick downwardly through the access tube31 after opening of the closure 34-. The construction shown in FIG. 2Ais particularly adapted for this purpose. Here it will be observed thatan insulating link 89 is threaded at t ll to the upper end of the upperfuse terminal m. The upper end of the insulating link $9 is threaded at91 to a metallic stud M which is welded or brazed at @3 to a lowercompression plate Q4 which extends transversely of the upper end of theinsulating housing 18 and bears against the upper side of a radiallyinwardly extending annular rib 5. The upper end of the metallic stud )2is threaded at 96 for receiving the lower end of attachment means, showngenerally at 97. The attachment means 97' includes a metallic rod 98 thelower end of which is threaded at 99 for receiving the threaded upperend lid of the stud 92. At its upper end the metallic rod 98 is providedwith an operating ring or eye liltl for receiving a book of a live linetool which can be rotated axially of the access tube 31 and alsowithdrawn therethrough. lt will be understood that an endwise pullapplied to the operating ring or eye 1% of the attachment means d7causes the withdrawal of the connecting conductor means 59.

Preferably the upper end of the insulating housing 18 is sealed toprevent the entrance of moisture. The seal is arranged and constructedto the end that it can be applied when the connecting conducting means59 is inserted downwardly through the access tube 31 into operativeposition. Also it is arranged to become unsealed prior to the removal ofthe connecting conductor means 59 from the insulating housing 18. Forthese purposes a bellows M93 of rubber like material such as neopreneand indicated, generally, at W3 is provided. The bellows lit? has abottom res that is bonded at 195 to the upper side of the lowercompression plate 94. Also the bellows 1% has a top 1636 which is bondedat M7 to the under side of an upper compression plate 108. Overlying theupper side of the upper compression plate res is an annular flange 10?that is formed integrally with or is secured to the metallic rod 98.

When the connecting conductor means 59 is applied in operative positiondownwardly through the access tube 31 and into the insulating housing18, the arrangement is such that the corrugated annular side Wall fillof the bellows M33 moves readily into the upper end of the insulatinghousing 18. After the connecting conductor means has been properlylocated as determined by the engagement of the under side of the lowercompression plate 94 with the upper side of the annular rib 95, theoperator or live line stick in engagement with the operatring or eye andis rotated to screw the metallic rod onto the threaded upper end 96 ofthe metallic stud $2. This causes the upper compression plate 198 to bemoved toward the lower compression plate 94 and to expand the corrugatedannular side wall 11% of the bellows 1% against the juxtaposed innersurface of the upper end of the insulating housing 18 and against acylindrical back up tube lliti. This provides a sealed connection whichcan be removed by rotating the metallic rod 98 in the reverse direction.

The construction shown in FIGS. 4A4B of the drawings is generallysimilar to that illustrated in FIGS. 2A- 2B and described hereinbefore.The insulating housing l8 shown in FIGS. 4A-4B is slightly smaller thanthe insulating housing 18 shown in FlGS. 2A2B. Accordingly, the bellowsM93 and some of the associated parts are correspondingly reduced insize.

In the construction shown in FIGS. 4A4B lower and upper terminals lidand 117 are provided and they have integrally formed upstanding anddepending contact fingers 13 .8 and 119 for engaging the lower fuseterminal se and the upper fuse terminal til, respectively. Gartersprings 120 and 121 serve to bias the contact fingers 118 and 15.9inwardly. The terminals lllfi and 117 are pro vided with radiallyinwardly extending annular flange portions 122 and 123 between which aliner 124 of nylon or other similar insulating material is located. Oncethe assembly has been made it is not intended that the liner 124 will beremoved. Since the removable feature is not provided in the constructionshown in FIGS. 4A-4B, it is possible to use a smaller diameter ofinsulating housing ill.

It will be understood that a connecting bar or blade can be providedbetween the lower fuse terminal 69 and the upper fuse terminal 61 whenthe connecting conductor means 5'9 is to be employed solely fordisconnecting purposes. in such case provision is made for securing thetrailer to the lower end of the modified construction to serve for areextinguishing purposes in the manner described.

What is claimed as new is:

1. In an underground. high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, and attachment means atthe upper end of said connecting conductor means for receivhig anoperating member inserted in said access tube from its upper end toapply and remove said connecting conductor means through said accesstube.

2. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end or" eachin close proximity, in combination, an access tube for extendingupwardly irom the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinconnecting said upper and lowe terminals, attachment means at theupper end of said connecting conductor means for receiving an operatingmember inserted in said access tube from its upper end to apply andremove said connecting conductor means through said access tube, and ametallic chamber extending from the lower end of said insulating housingand completely sealing oil the same.

3. in an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extending uiwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterterconnecting said upper and lower terminals, attachment means atthe upper end of said connecting conductor means for receiving anoperating member inserted in said access tube from its upper end toapply and remove said connecting conductor means through said accesstube, and expansible and contractible sealing means at said upper end ofsaid insulating housing operated by said attachment means under thecontrol of said operating member for sealing off said upper end of saidinsulating housing.

4. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of verticallyspaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, attachment means at theupper end of said connecting conductor means for receiving an operatingmember inserted in said access tube from its upper end to apply andremove said connecting conductor means through said access tube, ametallic chamber extending from the lower end of said insulating housingand completely sealing oil the same, and expansible and contractiblesealing means at said upper end of said insulating housing operated bysaid attachment means under the control of said operating member forsealing oil said upper end of said insulating housing.

5. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebe veen, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember Wl 11 each arm for connection at its outer end to the respe "veconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecking conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, attachment means at theupper end of said connecting conductor means for receiving an operatingmember inserted in said access tube from its upper end to apply andremove said connecting conductor means through said access tube, saidattachment means including an eye member to receive said operatingmember and thereadably mounted on the upper end of said connectingconductor means, upper and lower compression plates extending inparallel spaced relation with said upper end of said insulating housing,said lower compression plate being movable with said connectingconductor means and said upper compression plate movable with said eyemember whereby said compression plates are movable relatively toward andaway from each other, and a bellows of rubber-like material interposedbetween said compression plates and expandable into sealing relationwith the inner wall of said upper end of said housing on predeterminedrelative movement of said compression plates toward each other as aresult of rotation of said eye member by said operating member.

6. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulatin arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, said connectingconductor means being in the form of an expulsion type fuse having adischarge terminal at its lower end, a metallic exhaust chamberextending from the lower end of said insulating housing and completelysealing oil the same for receiving the are products from said fuse onblowing thereof, and attachment means at the upper end of saidconnecting conductor means for receiving an operating member inserted insaid access tube from its upper end to apply and remove said connectingconductor means through said access tube.

7. In an underground hi h voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, said connectingconductor means being in the form of an expulsion type fuse having adischarge terminal at its lower end, a trailer of insulating material atthe lower end of said discharge terminal, means slidably mounting saidtrailer relative to said discharge terminal, means biasing said trailerinto a position closing off st id discharge terminal to prevent areproducts discharged therethrough from returning, a metallic exhaustchamber extending from the lower end of said insulating housing andcompletely sealing off the same for receiving the are products from saidfuse on blowing thereof, and attachment means at the upper end of saidconnecting conductor means for receiving an operating member inserted insaid access tube from its upper end to apply and remove said connectingconductor means through said access tube.

8. In an underground high voltage electric power dis tribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, an insulating linerwithin said insulating housing extending between said upper and lowerterminals and surrounding said connecting conductor means and acting toprotect said insulating housing from the heat of an are drawn from saidlower terminal on withdrawal of said connecting conductor means underload, and attachment means at the upper end of said connecting conductormeans for receiving an operating member inserted in said access tubefrom its upper end to apply and remove said connecting conductor meansthrough said access tube.

9. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescopcd with thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, upper and lower terminals in said insulating housingconnected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, an insulating linerwithin said insulating housing extending between said upper and lowerterminals and surrounding said connecting conductor means and acting toprotect said insulating housing from the heat of an are drawn from saidlower terminal on withdrawal of said connecting conductor means underload, means removably mounting said liner between said terminals, andattachment means at the upper end of said connecting conductor means forreceiving an operating member inserted in said access tube from itsupper end to apply and remove said connecting conductor means throughsaid access tube.

10. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, an insulating housing having its upper end telescoped within thelower end of said access tube and a sealed connection therebetween, apair of vertically spaced insulating arms extending laterally from saidinsulating housing toward said insulated conductors having a terminalmember within each arm for connection at its outer end to the respectiveconductor, insulation surrounding each connection between a terminalmember and the respective insulated conductor, a metallic shield aroundsaid insulation for each connection, a ground rod extending downwardlythrough said access tube past said insulating housing and connected tosaid metallic shields, upper and lower terminals in said insulatinghousing connected to the respective inner ends of said terminal members,connecting conductor means within said insulating housing for detachablyinterconnecting said upper and lower terminals, and attachment means atthe upper end of said connecting conductor means for receiving anoperating member inserted in said access tube from its upper end toapply and remove said connecting conductor means through said accesstube.

ll. In combination, a tubular insulating housing having a terminal atone end, an expulsion fuse slidably mounted within said housing andhaving a discharge terminal at one end normally in contact engagementwith said terminal on said insulating housing and movable with saidexpulsion fuse into said housing, a tubular trailer of insulatingmaterial slidably mounted relative to said dis charge terminal andarranged when drawn into said housing with said expulsion fuse to haveits outer surface juxtaposed to the inner surface of said housing, and acoil compression spring within said tubular trailer biasing it into aposition closing off said discharge terminal to prevent are productsdischarged therethrough from returnmg.

12. The invention, as set forth in claim 11, wherein a metallic shieldis mounted on the end of the trailer upon which the are productsimpinge.

13. The invention, as set forth in claim 11, wherein an exhaust chamberclosed to the atmosphere is connected to the one end of the tubularinsulating housing and constitutes an endwise extension thereof forreceiving the are products from the discharge terminal on blowing of theexpulsion fuse.

14. In combination, a tubular insulating housing carrying internalterminals in spaced relation therealong, an expulsion fuse havingterminals engaging said terminals on said housing and movable endwisewithin said housing into and out of contact engagement therewith, one ofsaid terminals of said expulsion fuse being a discharge terminal throughwhich are products incident to blowing of the fuse flow, a trailer ofinsulation slidably mounted relative to said discharge terminal, andmeans biasing said trailer into a position closing off said dischargeterminal to prevent said are products from returning into said expulsionfuse, movement of said expulsion fuse out of engagement with saidterminals within said housing under load drawing an arc between saiddischarge terminal and the associated terminal within said housing whichis confined between the inner surface of said housing and the outersurface of said trailer.

15. In combination, a tubular insulating housing carrying internalterminals in spaced relation therealong, an expulsion fuse havingterminals engaging said terminals on said housing and movable endwisewithin said housing into and out of contact engagement therewith, one ofsaid terminals of said expulsion fuse being a discharge terminal throughwhich are products incident to blowing of the fuse flow, an exhaustchamber forming an extension of said housing to receive said areproducts, a trailer of insulation slidably mounted relative to saiddischarge terminal, and means biasing said trailer into a position closing off said discharge terminal to prevent said arc products dischargedinto said exhaust chamber from returning into 3. l c said expulsionfuse, movement of said expulsion fuse out of engagement with saidterminals within said housing under load drawing an are between saiddischarge terminal and the associated terminal within said housing whichis confined between the inner surface of said housing and the outersurface of said trailer.

16. in an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination, an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, a housing having its upper end joining with the lower end of saidaccess tube and a sealed connection thereoetween, a pair of verticallyspaced insulating arms extending laterally from said housing toward saidinsulated conductors having a terminal member within each arm forconnection at its outer end to the respective conductor, upper and lowerterminals in said housing connected to the respective inner ends of saidterminal members, connecting conductor means within said housing fordetachably interconnecting said upper and lower terminals, andattachment means at the upper end of said connecting conductor means forreceiving an operating member inserted in said access tube from itsupper end to apply and remove said connecting conductor means through 25said access tube.

17. In an underground high voltage electric power distribution systemincluding a pair of buried insulated conductors having one end of eachin close proximity, in combination; an access tube for extendingupwardly from the vicinity of said ends of said conductors to groundlevel, a housing having a sealed connection to the lower end of saidaccess tube, upper and lower terminals in said housing in insulatedspaced relation and aligned with said access tube, means forelectrically connecting said upper and lower terminals to said endsrespectively of said buried insulated conductors, connecting conductormeans having electrically connected upper and lower ferrules fordetachable engagement respectively with said upper and lower terminals,and attachment means at the upper end of said connecting conductor meansfor receiving an operating member inserted in said access tube from itsupper end to apply and remove said connecting conductor means throughsaid access tube.

References Cited in the file of this patent

17. IN AN UNDERGROUND HIGH VOLTAGE ELECTRIC POWER DISTRIBUTION SYSTEMINCLUDING A PAIR OF BURIED INSULATED CONDUCTORS HAVING ONE END OF EACHIN CLOSE PROXIMITY, IN COMBINATION; AN ACCESS TUBE FOR EXTENDINGUPWARDLY FROM THE VICINITY OF SAID ENDS OF SAID CONDUCTORS TO GROUNDLEVEL, A HOUSING HAVING A SEALED CONNECTION TO THE LOWER END OF SAIDACCESS TUBE, UPPER AND LOWER TERMINALS IN SAID HOUSING IN INSULATEDSPACED RELATION AND ALIGNED WITH SAID ACCESS TUBE, MEANS FORELECTRICALLY CONNECTING SAID UPPER AND LOWER TERMINALS TO SAID ENDSRESPECTIVELY OF SAID BURIED INSULATED CONDUCTORS, CONNECTING CONDUCTORMEANS HAVING ELECTRICALLY CONNECTED UPPER AND LOWER FERRULES FORDETACHABLE ENGAGEMENT RESPECTIVELY WITH SAID UPPER AND LOWER TERMINALS,AND ATTACHMENT MEANS AT THE UPPER END OF SAID CONNECTING CONDUCTOR MEANSFOR RECEIVING AN OPERATING MEMBER INSERTED IN SAID ACCESS TUBE FROM ITSUPPER END TO APPLY AND REMOVE SAID CONNECTING CONDUCTOR MEANS THROUGHSAID ACCESS TUBE.